House dust mites of the genus Dermatophagoides are one of the most frequent indoor allergen sources worldwide and are potent inducers of perennial asthma and rhinitis. Several groups of allergens from the most important species (Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f)) are reported (http\www.allergen.org). The group 1 allergens (e.g. Der p 1 and Der f 1) and the group 2 allergens (e.g. Der p 2 and Der f 2) are considered the clinically most important allergens among house dust mites with IgE binding frequencies of more than 80 percent. Other known allergens from the genus Dermatophagoides have variable levels of IgE antibody titers, e.g. Der p 4, 5, 7, 8, 10, 11, 13-15, 18, 20, 21 and 23. In some tropical and subtropical regions of the world, the clinically most important mite allergens may be from both house dust mites and storage mites of which storage mites of the genus Blomia (e.g. of the species Blomia tropicalis) may be more clinically important than of the genus Dermatophagoides. While the major allergens of the species Der p and Der f are highly cross-reactive and have sequence identity of above 80-85%, the sequence identity to the corresponding allergens in storage mite species are much lower (below 40-50%).
Allergen-specific immunotherapy (SIT) represents a causative and disease-modifying approach with long-lasting effects with the efficacy of reducing the symptom burden and concomitant medication use. SIT is based on the administration of increasing doses of the disease-eliciting allergens into sensitized subjects in order to achieve a state of clinical tolerance to subsequent exposure. Conventionally, SIT includes subcutaneous injection (SCIT) or sublingual administration (SLIT) of a pharmaceutical formulation of an allergen extract of the disease-eliciting allergen source, e.g. an allergen extract of house dust mite bodies and fecal particles. Conventional SIT may induce severe side-effects in allergic patients, e.g. anaphylaxis, though SLIT has been proven to have a superior safety profile to SCIT. However, the risk of inducing anaphylaxis is still not negligible because the allergen extracts contains considerable amounts of IgE-reactive allergens. This may limit the broad applicability of this treatment approach.
Current SIT products on the market target either house dust mite allergy or storage mite allergy. Thus, patients with dual sensitization to both house dust mite species and storage mite species may not be well treated by current SIT products.
Accordingly, an unmet need exists in the art for allergy immunotherapeutic products with high safety profile and efficacy to both house dust mites and optionally storage mites.